1. Field of the Invention
The present invention is directed to temperature-controlled shipping containers and methods for transporting products utilizing temperature-controlled shipping containers. In particular, the present invention is directed to temperature-controlled shipping containers that include a sorption cooling unit to maintain the internal temperature of the shipping container below ambient temperature.
2. Description of Related Art
The shipment of products that must have their temperature maintained within a specific range below ambient is one of the fastest growing market segments in the modern shipping industry. This growth is driven by a number of factors including widespread concerns about safety in the cold food distribution chain, increasing numbers of pharmaceutical and life sciences products which must have their temperature maintained within certain limits, the rapid growth in high-value specialty chemicals such as those used in the semiconductor industry, the increasing number of sophisticated medical tests which require the shipment of patient specimens to an external laboratory, the increased number of clinical trials associated with new pharmaceutical discovery and the increased delivery of products directly to the customer as a result of Internet ordering.
This field is generally referred to as controlled temperature packaging (CTP). CTP can be segmented by the target temperature range, namely: frozen (below 0xc2x0 C.); 2xc2x0 to 8xc2x0 C., and less than ambient (e.g., less than 30xc2x0 C.). In addition, CTP may be segmented by container size, namely: greater than pallet; one cubic foot to pallet; and less than one cubic foot. Containers having a size greater than pallet are typically cooled by mechanical refrigeration and the shipment times are typically from days to many weeks. The one cubic foot to pallet size segment is dominated by systems using ice (e.g., gel packs) and/or dry ice as a coolant wherein the containers are insulated using expanded polystyrene (EPS). The market segment for containers less than one cubic foot in size is very limited due to an unmet need for a small, lightweight cooling mechanism.
Although many basic ice/EPS systems are in use, there is a wide variation in quality and performance of the packaging depending on the value of the product and the sensitivity of the product to temperature fluctuation. A relatively simple system includes a cardboard box into which EPS sheets have been cut and placed. The container is then filled with dry ice in which, for example, frozen fish is shipped. A more sophisticated approach is a validated system consisting of custom molded EPS forms in a rigid box with both frozen and warm gel packs, the combination of which has been tested through a range of temperature cycles for specified thermal properties. Such a validated system can be used for shipping pharmaceuticals. For example, many pharmaceutical products such as vaccines and antibodies must be maintained at 2xc2x0 C. to 8xc2x0 C.
The existing ice/EPS cooling system is unsatisfactory because of increased environmental concerns associated with disposal of large quantities of EPS and gel packs, along with the high cost of shipping. Gel packs also require freezers at the shipping source to maintain the frozen packs. The high cost of shipping is directly related to the high volume associated with the EPS and the high volume and mass associated with the gel packs. As an example, for a one cubic foot box with a 60 hour lifetime at 2xc2x0 C. to 8xc2x0 C., over 90 percent of the volume is consumed by EPS and gel packs. Some reduction in volume and shipping costs may be obtained by using vacuum insulation panels (VIPs), but the high cost of VIPs has precluded significant market penetration.
An example of the foregoing system is illustrated in U.S. Pat. No. 5,924,302 by Derifield issued on Jul. 20, 1999. This patent illustrates a shipping container that includes a plurality of cavities adapted to receive a coolant (e.g., gel packs) that surround a cavity adapted to receive an item to be shipped.
Electrically cooled shipping containers are also known, as illustrated in U.S. Pat. No. 6,192,703 by Salyer et al. issued on Feb. 27, 2001. This patent discloses a portable refrigerator unit and storage container employing vacuum insulation panels and a phase change material. Phase change materials undergo a change in physical form (e.g., solid to liquid) thereby absorbing heat from the surrounding environment. A battery driven refrigeration system provides cooling of the shipping container.
There is a need for a temperature-controlled container, such as a shipping container, having a lightweight cooling mechanism that does not occupy a large volume. It would be advantageous if the temperature of the container was controllable over a range of temperatures.
The present invention is generally directed to a temperature-controlled containers, such as shipping containers.
In one preferred embodiment, a temperature-controlled shipping container is provided that includes at least one sidewall and top and bottom walls defining a cavity that is adapted to contain a product within the cavity. A sorption cooler including an evaporator, an absorber and a vapor passageway disposed between the evaporator and the absorber is provided wherein the evaporator is disposed in thermal communication with the cavity to provide cooling to the cavity. A liquid reservoir is in liquid communication with the evaporator to provide liquid from the liquid reservoir to the evaporator.
According to this embodiment, one of the top, bottom and sidewalls can be fabricated from corrugated cardboard or a more insulative material such as polystyrene or a vacuum insulation panel. For example, at least one of the top, bottom and sidewalls can include a material having an insulative value of at least about R-3.
According to another embodiment of the present invention, a temperature-controlled shipping container is provided which includes an insert having top, bottom and sidewalls defining a cavity within the insert wherein at least one of the top, bottom and sidewalls has an insulative value of at least about R-3. The absorption cooling unit is incorporated in the insert wherein the absorption cooling unit includes an evaporator positioned adjacent to or within the cavity to provide cooling to the cavity. An external container, such as a cardboard container, can be provided to encase the insert. The insert can include insulative materials such as polystyrene or vacuum insulation panels. The absorber of the sorption cooling unit is preferably disposed on an outer surface of the insert to dissipate heat to the exterior of the insert. Accordingly, the container encasing the insert can include venting means to vent the heat generated by the absorber.
According to yet another embodiment, a temperature-controlled container is provided which includes top wall, bottom wall, and at least a first side wall defining a cavity wherein at least one of the top, bottom and side walls has an insulative value of at least about R-3. A sorption cooling unit is provided to provide cooling to the cavity.
According to this embodiment, the top wall, bottom wall or side wall can include polystyrene or a vacuum insulation panel or can be fabricated from cardboard. Further, at least a portion of one of the top, bottom and sidewalls can be defined by the surface of the evaporator which provides cooling to the cavity.